1. Field of the Invention
The present invention relates to a correlation calculation method, a correlation calculation device, a focus detection device and an image-capturing apparatus.
2. Description of Related Art
A focus detection device such as that disclosed in Japanese Laid Open Patent Publication No. 2007-333720, calculates the extent of displacement (image shift amount, shift amount) indicating the relative displacement between a pair of data strings corresponding to a pair of images manifesting distortion relative to each other. This device calculates a correlation quantity indicating the degree of correlation by adjusting a shift amount k based upon a correlation operation expression that includes multiplication of the data in the pair of data strings.